1. Field of the Invention
The invention relates in general to an injection locked frequency divider, and more particularly to an injection locked frequency divider having a wider injection locked frequency range.
2. Description of the Related Art
With the progress of the communication industry, a high-frequency phase lock loop (PLL) has been widely applied to various wired and wireless communication systems, such as frequency synthesizers or clock generators. In the high-frequency PLL, a high-frequency frequency divider, which is one of the indispensable components, can receive an original signal and lower the frequency by dividing the frequency of the original signal by one or different values.
An injection locked frequency divider is frequently used in the industry and has the architecture, in which a signal injection unit and a voltage controlled oscillator are combined. In the present technology, only the injection locked frequency divider implemented by a LC tank oscillator exists. However, the LC tank oscillator has the narrower injection locked frequency range. So, it is an important subject of the invention to provide another type of injection locked frequency divider circuit capable of effectively enhancing the injection locked frequency range of the injection locked frequency divider.